Non-linearity caused by servomotor:

The correct answer is option 'C' - Saturation.

Explanation:

Servomotors are widely used in various control systems to achieve precise and accurate control of position, velocity, and torque. However, they are not perfect and can introduce non-linearities that affect the performance of the system. One such non-linearity is saturation.

Saturation refers to a condition where the output of the servomotor reaches its maximum or minimum value and cannot increase or decrease any further. This occurs when the input signal to the servomotor exceeds its limits or the motor itself is unable to generate the desired output due to physical limitations.

Below are the key points explaining why saturation causes non-linearity in servomotors:

1. Definition of saturation:
Saturation is a phenomenon that occurs when the servomotor cannot produce the desired output even when the input command signal increases. This can be due to various factors such as voltage limitations, current limitations, or mechanical limitations of the motor.

2. Impact on linearity:
Linearity refers to a linear relationship between the input and output of a system. In an ideal servo system, the output would be directly proportional to the input signal. However, when saturation occurs, the output no longer follows a linear relationship with the input. This introduces non-linearity in the system.

3. Effect on control performance:
Saturation can have a significant impact on the performance of a control system. When the servomotor saturates, it can lead to a loss of control authority, reduced accuracy, and slower response times. This can be especially problematic in applications that require precise control, such as robotics, CNC machines, and automation systems.

4. Causes of saturation:
Saturation can be caused by various factors. In the electrical domain, it can occur due to voltage or current limitations in the motor or power supply. In the mechanical domain, it can occur due to physical limitations of the motor, such as the maximum torque it can generate or the maximum speed it can achieve.

5. Mitigation strategies:
To mitigate the effects of saturation, several techniques can be employed. These include using higher-rated motors or power supplies, implementing control algorithms that compensate for saturation, and employing feedback mechanisms such as current or torque control to prevent the motor from saturating.

In conclusion, saturation is a non-linearity caused by servomotors. It occurs when the motor is unable to generate the desired output due to physical or electrical limitations. Saturation can have a detrimental effect on the performance of control systems and needs to be carefully considered and mitigated in order to achieve accurate and precise control.